[apps/tidep0084.git] / example / iot-gateway / node_modules / engine.io / lib / transports / polling-jsonp.js
2 /**
3 * Module dependencies.
4 */
6 var Polling = require('./polling');
7 var qs = require('querystring');
8 var rDoubleSlashes = /\\\\n/g;
9 var rSlashes = /(\\)?\\n/g;
11 /**
12 * Module exports.
13 */
15 module.exports = JSONP;
17 /**
18 * JSON-P polling transport.
19 *
20 * @api public
21 */
23 function JSONP (req) {
24 Polling.call(this, req);
26 this.head = '___eio[' + (req._query.j || '').replace(/[^0-9]/g, '') + '](';
27 this.foot = ');';
28 };
30 /**
31 * Inherits from Polling.
32 */
34 JSONP.prototype.__proto__ = Polling.prototype;
36 /**
37 * Handles incoming data.
38 * Due to a bug in \n handling by browsers, we expect a escaped string.
39 *
40 * @api private
41 */
43 JSONP.prototype.onData = function (data) {
44 // we leverage the qs module so that we get built-in DoS protection
45 // and the fast alternative to decodeURIComponent
46 data = qs.parse(data).d;
47 if ('string' == typeof data) {
48 //client will send already escaped newlines as \\\\n and newlines as \\n
49 // \\n must be replaced with \n and \\\\n with \\n
50 data = data.replace(rSlashes, function(match, slashes) {
51 return slashes ? match : '\n';
52 });
53 Polling.prototype.onData.call(this, data.replace(rDoubleSlashes, '\\n'));
54 }
55 };
57 /**
58 * Performs the write.
59 *
60 * @api private
61 */
63 JSONP.prototype.doWrite = function (data, options, callback) {
64 // we must output valid javascript, not valid json
65 // see: http://timelessrepo.com/json-isnt-a-javascript-subset
66 var js = JSON.stringify(data)
67 .replace(/\u2028/g, '\\u2028')
68 .replace(/\u2029/g, '\\u2029');
70 // prepare response
71 data = this.head + js + this.foot;
73 Polling.prototype.doWrite.call(this, data, options, callback);
74 };